Electron discharge device having an electron beam passage and aligning means therewith for the cathode



Oct. 1948. P. M. DICKERSON 51,813

ELECTRON DISCHARGE DEVICE HAVING AN ELECTRON BEAM PASSAGE AND ALIGNING' MEANS THEREWITH FOR THE CATHODE Filed March 50, 1943 l 'l k ATlTn-rfi A In i INVENTOR PM fl/c rf/aso/v.

BY mum ATTORNEY Patented Oct. 19, 1948 ELECTRON DISCHARGE DEVICE HAVING AN ELECTRON BEAM PASSAGE AND ALIGNING MEANS THEREWITH FOR THE CATHODE Paul M. Dickerson, East Orange, N.J'., assignor to Westinghouse Electric Corporation, East Pittsburgh, Ifa, a corporationof Pennsylvania Application March 30, 1943, Serial No. 481,069

This invention relates to electron discharge devices and particularly to that character of apparatus utilizing a beam of electrons.

Ina beam-type of electron discharge device,

one of the re-requisites to efliciency thereof, is

that the cathode be accurately aligned. Such de vices of the general character illustratedin the accompanying drawing as heretofore manufactured and as shown in copending application, Serial No. 478,560, of March 9, 1943, and assigned to the same assignee as this application, required a considerable time to obtain the correct alignment during the fabricating process,famounting to approximately fifteen minutes each on an av erage. Not only was this very considerable time delay involved, but the aligning processfintr'o duced strains in the glass mounting which re-. sulted in defective sealing and thus produced an' objectionable amount of shrinkage in manufac-, ture. In general aspects of the invention, there? fore, an object is to overcome the deficiencies heretofore encountered in manufacture of, electron discharge devices of the beam type.

'From a more specific standpoint, an object of the invention is to provide a structure wherein the cathode is automatically aligned 'as a necessary product of the assembly thereof in the de vice.

Another object of the invention is to assure proper alignment of the cathode by the dimensions and interfitting such alignment. U M

A further object of the invention is to improve focusing of cathodes in devices as characterized and increase efiiciency of the device asawhole.

Yet other objects of the invention are toobtain rigidity of construction; to avoid vibration; to assure presence of adequate and uniform dielectric; to reduce handling of the parts and time consumed in assembly; and to obtain other advantages and results which will appear as the description progresses, both by direct recitation thereof and by implication from the context.

Referring to the accompanying drawing, in which like numerals of reference indicate. the same parts throughout, an exemplification of the invention has been arbitrarily selected for the present disclosure. p

Figure 1 is a view largely in longitudinal sec-'- tion, showingan electron discharge device of and backagain into the resonator. The perfoof the parts controlling 6 Claims. (Cl. 250-27.5)

2 the beam type with my invention incorporated in association with the cathode; and

Figure 2 is a perspective view of the dielectric collar and associated partof the focusing sleeve. In the specific embodiment of the invention illustrated'insaid drawing, the reference numeral with prior art ractice are applied to the cathl0 designates an electron discharge device in general of the beam type, and shown as constructed as abody of revolution about an axis. The usual structuralffeatures of such a device comprise a cathode II in a plane normal to the axis at adist'ance'from which is disposed a reflector t2 also normal to the axis, said axis passing through the centers of both the cathode and reflector. In: the region intervening between the cathode and refiector isa hollow resonant chamber J3 the opposite walls of which around the axisare perforate for passing the electron beam therethrough from thecathode'to the reflector ratepartsof the walls, for'want of better term, have been identified in theart as grids, and accordingly in the order of nearness to the cathode will behere identified as the near grid M' and 1 far grid liof the resonator. Between the cathode and said near grid of the resonator is a focusing gridlG, it preferably being situated as close as electrically and mechanically feasible to the cathode nppropriate potentials, in accordance ode, focusinghgrid, resonant body and reflector. The beam of electrons in its forward path will be bunched by passing through the constricted space between. the near and m, resonant chamber grids, and thus on the return passage through that spacewill be in concentrated bunches, and there giving up a large part of their energy to the resonant chamber. The resultant energy is carried off for useful purpose through an output from the resonant chamber, said output being here shown as afloop and concentric line H. One wall l8 off thje resonant chamber is made flexible for tuning the resonator by an adjustment of the spaced relation of the resonant chamber grids.

The outer shell is sealed and accordingly conto the u best the operator's ability both centrally with respect to the axis and perpendicular to the axis. According to the present invention, I eliminate this uncertainty of alignment and incorporate means affording positive alignment. The specific construction selected for illustration of this feature of the invention will now be described.

A ceramic or other insulator I9 is provided having a bottom disc-like portion 20 forwardly from which projects a cylindrical body or shoulder portion 21 i from which inturn projects a cylindrical neck 22, said bottom portion,'shoulder and neck all being coaxial and successively of smaller diameter. plied an inverted. metallic cup the sidewall of which is considerably longerthan the neck with its margin in fitting engagementwitlitheperipheral wall of the neck, and itsedge inengagement with the forward face of the; body or shoulder portion 2|. The forward end face of" this me-; tallic cup is in a plane normal to the axis and constitutes afore-mentioned cathode H, bein appropriately coated or otherwise rendered electron emissive. Within ,the cup is a suitable heater 23 having lead-in wires 24 extending through the'ceramic. It may also be here noted that a lead-in wire 25, also extending through the ceramic, constitutes a lead-in wire to the cathode for applying the desired potential thereto. Around the shoulder portion 2| in peripheral surface contact therewith, is a metallic focusing collar 26. This collarhas the same difference in diameterfro'm' the diameter of the cathode cup as the difference in diameters between the shoulder and neck portions of the ceramic. Themetallicfocusingcollar26 is, however, considerably longer than the cathode cup and extends both forwardly and rearwardly with respect thereto. Forwardly of the body'or, shoulder portion of the ceramic, the focusingcollar is concentric with and spaced from the cathode cup in precise parallelism in consequence of the rigid mounting of each uponthe ceramic. It is a simple manufacturing operation, by utilization ofan appropriate jig, to'position and Weld or otherwise attach the focusing grid inposition perpendicular to the axis of and within the focusing collar. Resultant upon the construction shown and method outlined, the assembly enables the focusing grid and emitting. face of" the cathode to be close, without touching, and inexact parallelism. 3

At the outside of and next the, forward margin of the focusing collar, is provided an" insulating ferrule, 28 in fittingperipheral surface engagement. The ferrule is furthermore preferably extended beyond the end of the collar and provided with an internal shoulderv 29 to engage over the end of the focusing collar. The inside diameter of this shoulder andof' the collar. arepreferably the same so as to provide a smooth inner pas,- sageway. The other end of the ferrule, that is, the near end to the cathode, has an. external peripheral flange 30. The exterior peripheral face of the ferrule and the forward'face of the flange seat snugly with respect'to a correspondingly shaped housing member 3| forming partv of the envelope between the cathode chamber and resonator chamber. The long'bearing engagement of the annular wall, of the ferrule with the housing member and with the focusing collar assures utmost precision in the assembled structure in addition to desired rigidity and non-vie brating mounting of the collar, ceramic insulator-andcathodei The presence of the ferrule be- Over the neck 22, is aptween the housing member and the focusing collar assures adequate and definite dielectric always separating those parts and furthermore enables the cathode to have a location within the housing member at desired distance from the near grid of the resonator.

I claim:

1. An electron discharge device comprising a housing formed as a body of revolution about an axis, an insulator coaxial with said housing, said insulator having an end thereof formed as a disc, having an opposite end formed as a neck, and having an intervening shoulder portion, said disc part of the insulator constituting a means mounting the insulator in the said device, a focusing collar mounted on and held coaxial with said shoulder portion, and a cathode mounted on and held coaxial. with the neck portion of the insulator, said collar being extended beyond the envelope an intermediate part whereof comprises a housing having a constricted passage for electrons, a cathode having, its emitted surface crosswise of and coaxial with said passage substantially at one end thereof, another electrode in said. envelope. coaxial with and opposite the other end of said passagaand a collar within said envelope and having one end portion projecting from said housing coaxially of said cathode and said projecting end portion supporting said cathode, said collar having its other end portion within and supported by said housing.

3. An electron discharge device comprising a housing having a passage for flow of a beam of electrons therethrougha cathode in said passage directed toward a far end thereof, another electrode opposite the far end of said passage for reception of the beam of electrons, a focusing collar around the cathode, an insulator in one end portion of said collar in engagement with both the cathode and collar bracing the cathode from said collar coaxially, and means interposed between the other end portion of said collar and housing" centering and aligning the collar and cathode.v

4. In an electron discharge device, a housing having a cylindrical passage for flow of a beam of electrons therethrough, an insulating ferrule within said housing, a focusing collar having one end portion within said ferrule and its other end portion. projecting from said ferrule, and a cathode Within said other and projecting end portion of and aligned by saidfocusing collar with respect to the ferrule and housing passage.

5. Anelectron discharge. device of the beamv type having a cathode and another electrode op' cusing collar in part surrounding, the cathodecoaxial. therewith, means, supporting both one end of said collar and. said cathode and maintaining rigid coaxial alignment of the cathode in said collar, a grid Within and crosswise of said collar and having close spacing to the cathode, and means at and rigidly supporting the other end of said collar and maintaining alignment of the collar and cathode with said electrode.

PAUL M. DICKERSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,072,957 McGee Mar. 6, 1937 2,170,663

OTHER REFERENCES Ser. No. 386,266, Messner et al. (A. P. 0.), pub- Painter Aug 22, 1939 15 fished May 1943- 

